DESCRIPTION: This grant application is focused upon fabricating arrays of sensor elements that will create specific patterns when exposed to mixtures of analytes. These patterns will allow for the simultaneous identification of the individual analytes in the mixture. As a proof of concept, we will use the sensor arrays to target common analytes in blood and urine samples. The inspiration for our sensing strategy derives from the mammalian sense of taste The sense of taste in mammals derives from both specific and nonspecific molecular recognition events at hundreds to thousands of receptor sites. Only four different types of signals are created: sweet, sour, salty, and bitter. Yet, the different combinations resulting from the absence and presence as wel as the intensity of these four signals is enough to create patterns that are recognized by the brain to be specific for different foods. It is the ability to use molecular recognition in a nonspecific manner to create a fingerprint for each taste that allows mammals to be very sensitive and selective with respect to food differentiation. The "electronic tongue" will be composed of polystyrene/polyethylene glycol resin beads that have been derivatized with libraries of nucleotides, peptides, thioureas, and guanidiniums. The libraries will also possess monomers that have been shown to induce secondary structures Further, fluorescent monomers that are exquisitely sensitive to local microenvironment will be incorporated into the libraries. The libraries will b screened for interactions with specific guests, and any members of the library showing specific or nonspecific recognition events will be incorporated into a micromachined platform. This platform will be comprised of wells for depositio of the beads, flow channels, UV/vis filters, and a charged-coupled device (CCD). Irradiation of the entire library with excitation light will create colorimetric/fluorescent signals resulting in patterns specific for the analyt solutions. These patterns will be stored in a computer for future reference, and for identification and quantitation of analytes in unknown samples.